In 1984 he diagnosed President Ronald Reagan on the basis of speech errors in his presidential re-election speeches in an article in the Sunday Times as having Alzheimer’s disease ten years before this was formally identified.[2][3][4] He was a coauthor in 1971 of a pamphet, Marked for life, critical of universityexaminations.[5]

He designed the world’s largest mathematical experiment involving over 18,000 people at Explore-At-Bristol.[6]. The results were announced in Sept 2003 and found that women were faster at subitizing.[7]

Subitizing concerns the ability to instantly identify the number of items without counting. Collections of four or below are usually subitized with collections of larger numbers being counted. Brian Butterworth designed an experiment that ran as an interactive exhibit at the Explore-At-Bristolscience museum to find whether subitizing differed between women and men. Participants were asked to estimate as fast as they could between one and 10 dots and press the answer on a touch screen. How long they took—their reaction time--was measured. Over 18,000 people took part—the largest number ever to take part in a mathematical cognition experiment.[7] He announced his finding that women were better than men at subitizing at the British Association for the Advancement of Science's 2003 annual science festival.[7] He also found that people were six per cent faster on calculating the number of dots if they were presented on the left side of the screen (and so right sided lateralized in the brain) but only if there were five or more and so counted.[7][8]